Performance metrics & physics
UV-B
UV-B is the shorter-wavelength ultraviolet band (280–315 nm) that causes sunburn and is largely blocked by ordinary window glass even before any film is added.
UV-B is the main driver of sunburn and is more energetic than UV-A. It does not penetrate skin as deeply but causes more immediate damage at the surface.
Standard automotive glass already blocks the majority of UV-B. Aftermarket window film adds marginal protection in this band — the main film benefit is closing the UV-A gap.
For comprehensive sun protection inside a vehicle, the combination of laminated windscreen plus UV-rejecting film yields very low transmitted UV.
